SF-SR02 Ultrasonic Module

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SF SR02.png
This module contains an ultrasonic sensor to detect the distance to an obstacle in front. It is usually used on robots to avoid obstacles. With the two holes, it can be installed easily on the robot. The sensor detects obstacles 2cm-700cm away, though it keeps stable signal output within 5m and the signals become weaker and weaker when it gets farther away from the obstacle beyond 5m.
There is power indicator light added onside to indicate power on/off. The 3-pin design makes it unique among most of the ultrasonic module in the market: the same pin to trigger and receive signals. The 3-pin anti-reverse cable included make the wiring tighter and more convenient. Also the beautiful cartoon design and the red PCB add to its fascination.
Note: Pin NSE is to burn firmware to the ship when it's manufactured and does not need to use later. If you hear some slight noise during the application, it's fine.


1) An ultrasonic module with a detecton range of 2cm-700cm; signals detected are stable within 5m, grow weaker beyond 5m and at last disappear
2) With a power indicator LED so you can tell whether it is powered
3) Auxiliary 3-pin anti-reverse cable, thus making the wiring tighter and convenient
4) Operating voltage: 5V; working current: 16mA
5) A cartoon shape with red PCB design, making it adorable and cute

Pin Function

GND: ground of the power
5V: 5V Supply
SIG: Trigger Pulse Input and Echo Pulse Output
NSE: No need to use; only used to burn the firmware to the chip when the module is manufactured.


Working Voltage DC5V
Working Current 16mA
Working Frequency 40Hz
Max Range 700cm, Ensured stable signal within 5m, gradually faded signal outside 5m till disappearing at 7m position.
Min Range 2cm
Trigger Input Signal 10uS TTL pulse
Echo Output Signal Input TTL lever signal and the range in proportion
Dimension 46x20.5x15 mm

Test Code

SF-SR02 Uno
5V 5V
NSE NOT Connected
 * Name:SF-SR02 Ultrasonic Module
 * Function:Detection the distance
For any technical questions, visit http://www.sunfounder.com/forum
//Email: service@sunfounder.com
//Website: www.sunfounder.com

#include <Wire.h>

#define SIG A0 //SIG attach to A0 of control board
unsigned long rxTime;
float distance;

void setup() 
  // put your setup code here, to run once:

void loop() {
  //set SIG as OUTPUT,start to output trigger signal to the module to start the ranging
  pinMode(SIG, OUTPUT);
  //Genarate a pulse 20uS pulse
  digitalWrite(SIG, HIGH);
  digitalWrite(SIG, LOW);
  //set SIG as INPUT,start to read value from the module
  pinMode(SIG, INPUT);
  rxTime = pulseIn(SIG, HIGH);//waits for the pin SIG to go HIGH, starts timing, then waits for the pin to go LOW and stops timing
  //  Serial.print("rxTime:");
  //  Serial.println(rxTime);
  distance = (float)rxTime * 34 / 2000.0; //convert the time to distance
  //leave the distance between 2cm-800cm
  if(distance < 2)
  if(distance > 800)
  Serial.print("distance: "); //print distance: 
  Serial.print(distance); //print the distance
  Serial.println("CM"); //and the unit


SF_SR02 Test CodeZIP.jpg
SGM324YS14 datasheetPDF.jpg